Sword Art Online: Hollow Realization Series by Tomo Hirokawa, Reki Kawahara, abec, Bandai Namco

Three years after the Sword Art Online incident, Kirito dives into a revamped Aincrad (now known as Ainground) in the new VRMMO Sword Art: Origin. As he progresses through the game with old friends and new, he meets a mysterious girl...

After a harmless dungeon-crawling adventure with Premiere escalates into a high-level battle called the "Ground Quest," Kirito discovers remnants of the floating castle of Aincrad-a world that should have been destroyed long ago. Determined to find more clues to the puzzle and uncover Premiere's identity, Kirito decides to delve deeper into this mysterious quest...Just what could be behind all of this?

Upon encountering their old elven friend Kizmel from Sword Art Online, Kirito and Asuna are sucked into another quest where dark elves and demons abound. After discovering that Silica and Premiere were transferred to the same world, the four decide to head to the quest checkpoint-the Forest of the Holy Tree. With the forest tainted by demon sorcery, the dark elves desperately need the power of the Holy Tree's priestess...And that priestess is Premiere?!

After the raid is interrupted by Kizmel's sudden entrance, the dark elf tells Kirito and Asuna about the Six Sacred Stones and the two goddesses living within game. Upon Seven's advice, Kirito visits the game operators for more clues, only to find the shocking truth behind Sword Art: The Origin!

Despite being identical, Premiere and Tia are actually polar opposites and-even worse-enemies. After learning of the sisters' unprecedented potential for world destruction, Kirito and the gang are forced to put their quest on hold in fear of losing their beloved Ainground and its NPCs. Meanwhile, Genesis, seeking to tap into the twin goddess's powers, challenges Kirito to a battle for Premiere! Which black swordsman will emerge victorious?!

Despite everyone's best attempts, the Great Separation and resurrection of Aincrad have begun to dismantle the world of SAO. Now Kirito and his friends must head straight into the heart of the floating castle and stop Premiere's other half, Tia, but can they make it in time to save their beloved game?! Stakes are high in this final showdown of Hollow Realization!